/?/ 



u 




'J 



f 



H3 



_me Distinctions in Our Cultivated 

•Barleys with Reference to Their 

Use in Plant Breeding 



A Thesis Submitted to the Faculty of the 

Graduate School of the University 

of Minnesota 



by 






HARRY V. HARLAN 

In Partial Fulfilment of the Requirements for 
the Degree of Doctor of Science 



1914 



..me Distinctions in Our Cultivated 

Barleys with Reference to Their 

Use in Plant Breeding 



A Thesis Submitted to the Faculty of the 

Graduate School of the University 

of Minnesota 



by 

HARRY V. HARLAN 



In Partial Fulfilment of the Requirements for 
the Degree of Doctor of Science 



1914 



SB |1» 



■V 



H3 



SOME DISTINCTIONS IN OUR CULTIVATED BARLEYS 

WITH REFERENCE TO THEIR USE IN 

PLANT BREEDING. 

By Harry V. Harlan. 



INTRODUCTION. 

When the writer began active operations in barley breeding in 
1909, the intelligent selection of mother plants was found to be very 
difficult because of the lack of sufficient information to enable minor 
variations to be recognized and interpreted. European breeders 
had subjected the taxonomic details to a most exacting scrutiny, but 
their results were not immediately useful. It was necessary to confirm 
the European findings, for a character found stable there could not be 
considered stable under the widely varying climatic conditions of 
America until it had been so proved. Again, the European authorities 
were far from united. There was not even a broad taxonomic char- 
acter whose stability had not been questioned at one time or another, 
and often by the highest authorities in barley classification. More- 
over, even if the groundwork could have been adopted entire, the 
more or less established taxonomic characters are only the beginning 
of the problem. Breeding must take note of characters that are 
trivial in taxonomy. The intangible must be analyzed and made 
to serve, as well as the tangible. 

Even the very plausible idea of adopting European methods and 
importing improved European stocks was only partially successful. 
Conditions in America differ in one vital particular from conditions 
in Europe. On the Continent and in Great Britain barley has been 
cultivated for centuries, and it is therefore practically indigenous. 
Each geographical locality has, through long periods of time, been 
provided by natural selection and acclimatization with superior 
native races. Breeding, under such conditions, is largely concerned 
with the improvement of these existing stocks, with small likelihood 
of any importation proving to be a serious competitor. 

In America there are no native stocks. The grain-producing areas 



2 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

are relatively new. The varieties peculiar to a section are usually 
the result of chance introductions. Breeding material from foreign 
sources is as likely to contain desirable types as is that already at 
hand. In this investigation, in order to obtain the proper basis upon 
which to conduct breeding work, stocks were assembled not only 
from local sources but from all over the world. Many distinct 
strains were isolated from each stock, for both the local varieties and 
the foreign introductions were usually either races that had not been 
purified or that had become mixed after purification. The isolation 
was accomplished by head and plant selections, which when grown 
in pedigree rows formed a surprisingly large collection. When to 
these were added a still greater number from the progeny of hybrids, 
the problem became one of elimination. The plant selections from 
their very nature were made more or less arbitrarily, and hundreds 
of these forms were necessarily duplicates. These duplicates, espe- 
cially as long as they were not so recognized, were a drain upon the 
breeder, and it was soon realized that the efficiency of a nursery was 
measured, not by the number of stocks it carried but by the number 
it eliminated. 

It was to accomplish this reduction better that the character 
studies were made. The distinctions found were of two classes, 
morphological and physiological. The morphological variations 
were, in the broader divisions, of taxonomic value, and many of 
them were practically invariable. The physiological characters 
were, from their nature, more difficult to appraise. They were found 
to possess not only more widely fluctuating limits, but the limits 
often overlapped and at times the characters became inseparable. 
In physiological characters a further distinction was made between 
permanent and place variations. Some separations were so wide 
that they never became confusing, while others became evident only 
when grown under certain conditions of soil and climate. Such dis- 
tinctions are worthless as taxonomic features, but have proved very 
valuable as indications of individual qualities in breeding. Even the 
lack of stability in a character does not destroy its usefulness, as 
the tendency of a strain to behave in a certain manner under certain 
conditions may mark an inherent difference. 

It is realized that distinctions of this kind are only a part of plant 
breeding, and it is not thought that that part is clarified in any 
great measure. In this paper are given a few of the observations 
that have been found useful in barley breeding, and with them many 
that have been found useless. The data upon which the conclusions 
are based consist of some 200,000 recorded observations, extending 
over a period of five seasons and embracing experiments at St. Paul, 
Minn. ; Williston and Dickinson, N. Dak. ; Highmore, S. Dak. ; Moc- 

Gift 



DISTINCTIONS IN CULTIVATED BARLEYS. 3 

casin, Mont. ; Aberdeen and Gooding, Idaho ; and Chico, Cal. Of 
the work done at these points, that at St. Paul, Minn., which was 
conducted in cooperation with the State experiment station, was the 
most extensive. 

REVIEW OF THE LITERATURE. 

Although the literature of barley is, with the possible exception 
of wheat, more extensive than that of any other cereal crop, the pub- 
lications bearing directly upon the theme of this paper are com- 
paratively few. The great mass of the European publications, 
especially the German ones, have to do with the malting quality of 
barley. They are concerned mostly with its chemical constituents, 
the effect of soil, climate, and culture upon the nature and composi- 
tion of the grain, and the behavior of the converting enzyms in 
grains of different character. The same is true of papers on the 
morphology of the grain, and even many of the publications treating 
directly of barley breeding have little bearing upon the present dis- 
cussion, as they are often concerned only with the correlation of 
characters or with the behavior of hybrids. It is only the papers 
dealing with the taxonomic features of barley, and experiments such 
as those of the Swedish Plant-Breeding Association at Svalof, 
which have had for their end the isolation of plant variants, that are 
of particular pertinence. 

The first comprehensive systematic work was that of Kornicke 
(15) 1 , who described 44 botanical forms of barley, using spikelet 
fertility, color, nature of the awn and glume, and the adherence or 
nonadherence of the palea. His groups will undoubtedly form the 
bases of all future classifications. The classification of Voss (25) is 
important largely because he based a part of it upon the extent of 
overlapping of the grains, thus forecasting in an indefinite way the 
use of density. Atterberg (2) made use of the bristle and nerve 
characters discovered by Neergaard, mentioned below, and subdi- 
vided the previous groups until he had 188 named botanical varieties. 
Beaven (3), by a rearrangement and compilation of previous classi- 
fications and by growing and describing a large number of hybrids 
of Karl Hansen, Kornicke, and others, gave a very clear conception 
of the entire species. His work is perhaps most valuable in the 
placing of the Abyssinian forms with abortive lateral florets in a 
group by themselves. He does not make use of the finer subdivisions 
employed by Atterberg. Regel (21) , on the contrary, carries the sub- 
division still farther and uses twisting of the spike and earliness and 
lateness of the variety in his separations. The last, a purely physio- 
logical phase, he employs in named botanical forms. 

A review of the work at Svalof is especially valuable in this con- 
nection because of the fact that a large part of that effort has been 

1 The figures in parentheses refer to the bibliography at the end of the bulletin. 



4 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

along the same line and because, in many instances, this investiga- 
tion has merely attempted to discover whether results obtained by 
them were sustained under the great variations of the American cli- 
mate. In barley the greatest achievement at Svalof was the dis- 
covery of two kernel characters, which, by various combinations, 
gave four separations under each previous group. 

These investigators found that the rachilla in some barleys was 
covered with long straight hairs and in others with short curly ones; 
also that the inner pair of dorsal nerves sometimes bore teeth and 
were sometimes smooth. The stability of these characters was ques- 
tioned by Broili (10), who claimed to have frequently observed one 
form in the progeny of another. Tschermak (13), Blaringhem (7), 
and others have supported the investigators of the Plant-Breeding 
Association at Svalof, at least so far as the basal bristle is concerned. 
Although none are to be compared with this discovery in importance, 
many other studies have been made at Svalof. At one time they had 
developed a very elaborate system of measurements made by means 
of many ingenious mechanical devices. They have, unfortunately, 
made no specific, comprehensive publication of their negative re- 
sults, but according to Newman (20) and others they have aban- 
doned the use of many of the measurements that were formerly 
made. Of those retained, the most important from the standpoint 
of this paper is that of density. In the early history of the asso- 
ciation two or three varieties were obtained by the "elite" method. 
They chose an arbitrary density and made mass selections of spikes 
conforming to that measurement. Later, they used density as a 
means of valuing head measurements, as a long head if loose might 
contain no more grains than a short one if compact. They finally 
employed it in varietal description. Blaringhem (7), who has fol- 
lowed the work of the Svalof association quite closely, used density 
as an indication of purity and to reveal the effect of climate. 

The morphological characters of the seed coat and the kernel have 
been treated by Kudelka (16) and Johannsen (14), but there is no 
suggestion of usable varietal differences. 

The composition of the grain has been studied by a few American 
and a large number of European scientists. Le Clerc and Wahl 
(17), who have made the most comprehensive of the American 
studies, have clearly demonstrated that composition is of slight use 
as a varietal character for, while there are differences, the effect of 
location and season is many times greater than that of variety. 

Color in barley has been employed by all systematists, but has 
received very little analytical attention. Brown (11) has a note on 
the color in the variety coendescens, and numerous authors have dis- 
cussed the occurrence of pigments in other plants. A recent article 
by Wheldale (26) treats of the chemical nature of anthocyanin and 
traces its origin from a glucosid. 



DISTINCTIONS IN CULTIVATED BARLEYS. 5 

THE RATE OF DEVELOPMENT. 

The rate of development, like all physiological characters, is sub- 
ject to considerable fluctuation within the strain. The distinctions 
are naturally much less absolute than those founded upon morpho- 
logical characters. They have, however, the advantage that they 
permit a greater number of separations. A plant structure usually 
has but two phases. It exists or it does not exist. With physiologi- 
cal characters this is not the case. The length of time required for 
one variety to mature may differ three days from that of a second 
or it may differ three weeks. From the standpoint of observation, 
the development of the plant is divided into three periods: (1) The 
early development from germination to the time of jointing, (2) the 
period of heading, and (3) the period of maturity. 

EARLY DEVELOPMENT. 

For some time the writer has maintained that the early growth is 
the stage of development at which selections of barley are most 
easily distinguishable. This period seems to have been neglected by 
plant breeders. There are few records of notes taken during this 
time, and even those breeders who have known the cereal crops best 
have based their selections at this period on an intangible something 
that enabled them to single out any new variation. 

During the summer of 1913 an attempt was made to analyze the 
intangible, with most encouraging results. In addition to careful 
observations on several hundred selections, 1,400 plants were chosen 
in the nursery and 1,700 in drill rows, upon which exact records 
were kept. One hundred plants were used in each variety. The data 
included the day upon which each of the 3,100 plants produced its 
second, third, and fourth leaves and its first tiller. The optically 
plausible became mathematically evident, and it was soon seen that, 
aside from the leaf character, there was ample justification for the 
separations made on appearance during the early stages of growth. 
As figure 1 shows, the selections rush through the early stages at an 
astonishing rate. A centgener which is only two days, or even one 
day, behind a second may be in an entirely different stage of develop- 
ment and may therefore present an appearance which in no way re- 
sembles that of the first. Yet the two barleys may be closely related 
strains and inseparable or separated with difficulty at maturity. 
The typical curves of the production of the second, third, and fourth 
leaves are always very sharp. In figure 1 the curve of tillering is 
more flat than is usually the case. The first of the third leaves 
emerges about the time of the appearance of the last of the second. 
The fourth leaf is produced in about the same relation to the third, 
but perhaps a little earlier. The first tillers are usually simultaneous 
with the fourth leaves, though in some varieties they appear earlier. 



6 



BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 



The tillering in most varieties is not completed as rapidly as is the 
production of the fourth leaf, and it is deterred by disease much 
more than is the leaf. 



iJb 

92 

88 
84 
80 

7e 

72 
68 
64 
60 
S6 






A 


~^~\ 




































r* 






/ 


































. — — 


i**^ 








/ 






























** 














t 




























/ 










































.' 














J 


























_ 


s 
















/ 
























** 




















/ 






















/ 






















/ 






















/ 






















/ 




















,-* 
























/ 


















/ 
























f8 




/ 


















9 1 


























/ 


















«/ 










































It 1 




Hi 
























_ 


It' 














J7 


.** 
























32 
28 


4 
















si 


b K/ 


























V 
















v/— 


6 


























~i/ 








V 








vV 


























>yi 


1/ 








W 






kl t 




























m 

/2 
8 


S 








v / 










































,0/ 








/ 




























T- 






^ 








( 


































v 








f 




























O 














fc" 































K 23 24 25 26 27 2a 29 30 3/j ^/_ 



/O // /2 /3 /*, 



Fig. 1. — Curves showing the production of the second, third, and fourth leaves and of the 
first tiller in 96 plants of Oderbrucker barley (selection No. 50). 

Besides the difference in dates there is a difference in method of 
production. In some varieties the curve of each stage is very acute 
and the stage is completed in a few days. In others it is more obtuse 





/ 


































\ 














































































































i 






























1 


\ 


i 












\ 


f 










l " 




V 1 ' 

1 
















\ 


1 
1 




\ 

\ 
\ 
1 


> 


^ 




«**■» 


r 
















■sv 


V 













7 


































J- 








































i> 


































y 
































































































V 
























































1 


\ 




/ 












py 














^ 


I 














































\ 


/ 


\ 


f 






\ 


/ 


\ 


/ 


s 


/ 




s 


/ 






































< 


/ * 


3 1 


? £ 


4 - 


r / 








-■■ .: 


9 / 


? 3 


1 3 


* J 


' i 


J 


t J3 



^-TLScrrro/v 



0r jnM//VJ. 



Fig. 2. — Curves showing varietal differences in 
the rapidity of tillering of barley selections. 
In Eagle (No. 13) all plants produce tillers 
almost simultaneously, while in Russian (No. 
21) the process is extended over many days. 



Fig. 3. — Curves showing the average date 
of the production of the second and 
third leaves and of the first tiller in 100 
plants of each of 17 selections of barley 
grown in drill rows. 



and the time for completion extended. Figure 2 shows the relative 
rapidity of stooling in two selections, the one of the first type and 
the other of the second. 



DISTINCTIONS IN CULTIVATED BARLEYS. 7 

Differences are revealed in two ways by a comparison of the 
behavior of strains. There is an actual difference of date in any 
stage and, still more important, a relative difference between various 
stages. This is shown to some degree in figure 3, and to a still 
greater degree in figure 7, which will be discussed later. Figure 3 
shows the date upon which the greatest number of plants in 17 
selections sown in drill rows reached the three stages of development. 
It will be noticed that the average date of the occurrence of the 
second leaf varied over scarcely more than 1 day, while the third 
extends over 2-| days, and the production of tillers over 5 days. No. 
5, for instance, produces the third leaf 2 days after the second, while 
No. 13 requires another half day. Yet No. 13 requires but 3 addi- 
tional days to produce tillers, while No. 5 requires 5+ days. 

EMERGENCE OF THE AWNS. 

The time of heading is a general agronomic note, and there is no 
doubt that an observation of this period is of great value in plant 
breeding. Distinctions at this time shorld be easily made and 
should be more reliable than those of any later date. The difference 
between selections is greater than in the earlier stages, and the 
effect of season is not apparent in any abnormal hastening of devel- 
opment, as it is later in ripening. In any climate, most barleys 
develop in a fairly normal manner until flowering time. The time 
of heading, for these reasons, should be of great use. It has, how- 
ever, one disadvantage. It is an extremely difficult note to obtain, 
and hence inaccurate. Barleys differ very much in their manner 
of heading. Some heads are exserted rapidly and completely, others 
slowly and only partially. The observer has not only the difficulty 
of maintaining an arbitrary mental standard, but is confronted by 
numerous exceptions that never conform to any standard. 

In a study of this difficulty it was noticed that just previous to 
heading, the tips of the awns in all awned varieties projected from 
the boot of all plants in the selection with suggestive uniformity. 
The date of the emergence of the awns was substituted for the date 
of heading, with excellent results. The personal error was imme- 
diately removed and, as the facts could be gathered at a glance, the 
note taking was greatly accelerated. The change made a valuable 
plant-breeding observation out of a dubious agronomic note. 

Analyzed, the curve of date of emergence of the awns is almost 
as sharp as those representing the production of the leaves and 
tillers. Figure 4 shows the curve of 13,108 plants, a summary of 
the observations of a large number of selections. It will be noticed 
that nearly two-thirds of the plants pass through this stage in two 
days. A difference of a single day serves to change the appearance 



s 



BULLETIN 137. IT. S. DEPARTMENT OF AGRICULTURE. 



of a whole centgener, and strains that are three days apart are 

unbelievably dissimilar when viewed at this time. 

This note was taken for 
a large number of selec- 
tions for three years to test 
the transmissions of slight 
variations in earliness and 
lateness. The evidence 
seemed all in favor of ac- 
crediting to this character 
a heritability equal to that 
of most plant characters. 
The data are too cumber- 
some to include entire, but 
a random selection of 
strains of one general type 
is given in figure 5. The 
variations are parallel, on 
the whole, especially when 
it is remembered that the 
centgeners were often sep- 
arated by considerable dis- 
tances, allowing variations 
in soil and moisture. The 
exceptions are fully as 
likely to represent differ- 
ences in the character of 
the strains, causing them 
to respond differently to 
„ , , „ different seasons, as they 

Fig. 4. — Curve showing summary of data on the ' ". 

emergence of the awns in 13,108 plants from are to question the Value 01 
various selections of barley. the note. 





Fig. 5. — Curve showing the effect of season upon the relative date of the emergence 
of the awns in 37 selections of 6-rowed barley grown at St. Paul, Minn., in 1911, 
1912, and 1913. 



DISTINCTIONS IN CULTIVATED BARLEYS. 



DATE OF RIPENING. 

The date of ripening is a note universally taken. While less 
dependable than the emergence of the awns, it is a very useful obser- 
vation. Within a strain the plants mature quite uniformly. In 
order to determine the amount of such variation, the exact date of 
maturity of each spike in a plat of Manchuria barley was recorded. 
The spikes were considered ripe when the last traces of green dis- 
appeared from the glumes. In order to avoid confusion, they were 
harvested as fast as they ripened. The result is shown in figure 6. 
The curve is very sharp, almost half the product of the plat maturing 
upon the same day. 

The weakness of the note is 
in the abnormal ripening of va- 
rieties. In Minnesota the ob-. 
servation is quite dependable in 
Manchuria forms, but is likely 
to be much less so in the 2- 
rowed varieties. Some of the 
latter mature in a normal man- 
ner, while others, especially the 
later ones, half ripen and half 
die. Also, a rain at this period 
has much more influence in the 
development than at other times 
in the life of the plant. 



COMPARATIVE RATES OF DEVELOP- 
MENT. 



i 

i 






<J BOO 



\ /oo 






SO 8/ 32 83 84 8S 



Fig. 6. — Curve showing the ripening of 
1,541 spikes in a plat of Manchuria bar- 
ley, stated in days from date of planting. 



Although separations can be 
made by a study of any one of 
these stages, it is only when the 
entire seasonal histories of the 
selections are compared that the full variation is apparent. Figure 7 
shows the development of 14 strains from the production of the 
second leaf until maturity. Each stage was obtained by actual count 
of all the normal plants in each centgener, usually between 90 and 100. 

The relation of the earlier stages has already been commented upon. 
It will be noticed that the tillers are produced usually after the 
fourth leaves. In Nos. 34, 13, and 24 "this is not the case, and these 
three selections are definitely distinct from the other eleven by this 
different habit of tillering. Nos. 21 and 57 are parallel in the earlier 
stages but are widely separated in the emergence of the awn. No. 29 
is one of the earliest of all the selections to produce the second leaf, 

52783°— Bull. 137—14 2 



10 



BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 



and yet it is among the very latest in maturity. Indeed, there is 
some peculiarity about each one of the fourteen when all stages are 

considered. 

VARIATIONS IN THE CULM. 

The culm varies in length, diameter, thickness of walls, exsertion 
of spike, number of nodes, and number of culms per plant. 

LENGTH OF THE CULMS. 

The height of the plant is a note universally taken on all experi- 
mental farms. At any chosen station, some varieties are always tall 

and others always short. This 
distinction is sufficient to prove 
a difference between such va- 
rieties, and as such it is a use- 
ful observation in breeding. 
It is, however, merely a proof 
that a difference exists and is 
not necessarily a difference in 
itself. There is a physiologi- 
cal adaptation of varieties to 
certain places and it may ex- 
press itself in height. 

In 1911 thirteen pedigreed 
selections, representing nine 
minor groups of barley, were 
chosen from the nursery stock 
and planted at four widely 
separated points. At maturity 
the length of culm was care- 
fully noted. The influence of 
climate and soil was surpris- 
ingly great. As will be seen in 
Table I, there is a marked re- 
gional response. The selection 
of Odessa is a Hordeum sati- 
vum hexastichum form occur- 
ring in the commercial Odessa 
variety. In Minnesota it is 
short and unpromising. In 
California it is little better, 
while in the north Eocky 
Mountain and Plains areas it displays an unexpected vigor and is 
very tall. The Abyssinian varieties grow well in California, but are 
short elsewhere. 





6 

-? 

4 

3 

2 

/ 

3 1 

3 

23 

28 

2 7 


























y 




i 
















*v! 








/ 




















IN 








1 






'■' 














1 




\ 






/ 






* 














/ 




\ 






/ 




























\ 


/ 




























\ 


/ 


















H 










\ 


' 


















' 






























>1 






























? 




















25 
24 
23 

22 
21 
20 
13 
,8 
S 
4 
3 
2 
/ 
30 
23 
2,1 
27 
26 
25 
2V 
23 
.?.' 
Zl 
10 
9 

a 

7 
6 
S 

4 
3 

2 

31 
30 

23 
28 
27 
26 
25 
24 
[23 












" 






























• 




























'>/ 


















v 










VT/ 


















a' 










-M' 


















s 






















































































. 


















































,, Ujwvj 




1 


\ 
























^ 




1 


\ 


















'-/ 








^ 


/ 




















, ( V 






























& 




























f^ 
















































































X" 




























1 






























1 
























































































<Y 


/ 






















/ 


\ 




1 
























/ 


y 




















/ 


V 




/ 


y 
















' h 


\ 




/ 


V 




1 


\ 
















& 


s 




/ 


V 


/ 
























s 


/ 


\ 


/ 






























/ 


\ 














pi 












/ 


\ 


















|"Vi 










/ 


















A 






















k.-^ 




























/ 








F / 


■* 




















/ 


A 






w. 






















\ 


































-M 




















? 










& 








































/ 


\ 










"*§" 


< 






s 




/ 


s 




/ 


s 










Kv 






\ 




/ 


\ 




f 


















s 


z 




s 


S 










32 2 


1 3 




? a 

LCC 


4 3 

not* 


6 


I 2 

ftet 


9 j 


O 5 


o 

LAN 


■ 6 


1 5 


7 5 


? 



Fig. 7. — Curves showing the date of the 
production of the second, third, and 
fourth leaves and the first tiller, the 
emergence of the awns, and the day 
of ripening in 14 selections of barley 
grown at St. Paul, Minn., in 1913. Each 
determination was based on one centgener 
of approximately 100 plants. 



DISTINCTIONS IN CULTIVATED BARLEYS. 



11 



Table I. — Influence of geographical location on the length of the culm in IS 
representative selections of barley grown at four widely separated points, the 
selections being arranged in the order of their height at each point. 



St. Paul, Minn. 


WiUiston, N. Dak. 


Moccasin, Mont. 


Chico, Cal. 




Servian 




S. P. I. No. 20375. 




Odessa 


Hordeum vulgare 






Hordeum vulgare 


Abyssinian. 












Smyrna. 






S. P. I. No. 20375 

Kitzing, 6-rowed 








S. P. I. No. 20375 






Kitzing, 2-rowed 


Kitzing, 6-rowed 

S. P. I. No. 20375 




Kitzing, 6-rowed. 




Smyrna 




Kitzing, 2-rowed. 
Surprise. 
Hordeum vulgare. 




Abyssinian 


Kitzing, 2-rowed 

Princess 




Kitzing, 2-rowed 





The great variation evidenced by these few selections is sufficient 
to show that the length of culm can not be of much taxonomic value. 
There are varieties which are persistently below average height, and 
others that are as persistently above, but beyond that it is difficult to 
make an unqualified statement. Locally, this measurement is of 
more significance and can often be used to advantage in the study of 
nursery selections. The differences it reveals are important in 
breeding, no matter to what cause they may be due. 



DIAMETER OF THE CULMS. 



Measurements have not been found very useful in revealing small 
differences in the diameter of the culm. The experimental error is 
large, owing to the fact that the diameter varies on the same plant 
with the culm selected, on the same culm with the internode chosen, 
and on the same internode with the distance from the node. A part 
of this variation was avoided by measuring the greatest diameter of 
the first elongated internode, but even then the results were unsatis- 
factory. There are varietal differences, but they must be great 
enough to be seen optically before the error of measurement is re- 
duced to the point where it becomes negligible. As a group, the 
nutans has smaller culms than the Manchuria, but among the Man- 
churia strains there is little difference. Only once in these investi- 
gations has this character been used to isolate a type. This type has 
proved to be stable, and perhaps the effort of measuring hundreds of 
selections is rewarded by the one strain obtained, as it is very prom- 
ising. 



THICKNESS OF CULM WALLS. 



A large number of determinations were made of the thickness of- 
the walls of the culm, with even less satisfaction than in those of the 
diameter. Measurements finer than one-tenth of a millimeter are 
impracticable, owing to the variation within the plant and culm. 
This does not give range enough to disperse the varieties. For in- 



12 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

stance, of 242 selections of 6-rowed barley, the culms of 153 meas- 
ured 0.5 mm. in thickness and only 33 deviated more than 0.1 mm. 
from this figure. 

THE EXSERTION OF THE SPIKE. 

The exsertion of the spike is closely related to the length of culm 
because it depends upon the elongation of the peduncle. Some bar- 
leys clear the boot much more completely than others. That this is 
a true varietal character is shown by the number of varieties in 
which it has been described. The Princess in Sweden is often in- 
cluded at the base. The same is true of this variety in Minnesota 
and California. The Smyrna seldom clears the boot completely in 
more than one or two culms on each plant. An interesting fact was 
noted in this variety with reference to location. In Minnesota, half 
the head often remains in the boot, and the same condition prevails 
over the whole of the Plains area. In California, however, the heads 
are completely exserted. The exsertion is still short as compared with 
most varieties, but it is perfect. Like other physiological charac- 
ters, the exsertion of the spike is variable, but its range of variation is 
sufficiently limited to occasionally determine a variety. That it is 
not more often useful is due to the fact that almost all barleys are 
of the type in which the spike is completely exserted. 

NUMBER OF NODES PER CULM. 

The number of nodes to the culm is naturally identical with the 
number of leaves to the culm and is discussed under that heading. 

NUMBER OF CULMS PER PLANT. 

The number of culms per plant seems to be a varietal character, 
but one which is so dominated by environment as to make it impos- 
sible to determine when it is given true expression. It is probable 
that all students of the cereals have gone through the same process of 
diminishing confidence to final doubt as to the utility of this factor. 
In this investigation the number of tillers was recorded on over 
20,000 plants without being able to discover a method of using such 
information for minor distinctions, as was possible, for instance, 
with the time and method of tillering. The broad groups vary as 
groups in this character and occasionally a variety deviates suffi- 
ciently from its group to become distinct, but the mass is, for the 
most part, inseparable. 

Two causes of variation were studied in detail, viz, spacing and 
geographical location. In Minnesota a selection of Smyrna, a heavy- 
tillering variety of a 2-rowed group, and a light-tillering selection 
of Manchuria of the 6-rowed group were planted at three different 
spacings. The results obtained are shown in Table II. As will be 



DISTINCTIONS IN CULTIVATED BAKLEYS. 



13 



seen in this table, the varieties remained distinct in their tillering 
habit, but as the space decreased, the difference of over three culms 
per plant in favor of Smyrna rapidly diminished to one. Types 
falling between these extremes were inseparable at the least spacing. 
It will also be noticed that the varieties differ in the spacing at 
which they seem to make complete use of the soil. An increase in 
number of plants in the Manchuria beyond the 4 by 4 inch plant- 
ings does not increase the number of tillers on the unit area, while 
for Smyrna the limit is not yet reached. 



Table II.- 



-Effect of interval on the production of culms in selections of Smyrna 
and Manchuria 1 barley. 





Space between plants. 


Plants and culms. 


4 by S inches. 


4 by 4 inches. 


4 by 2 inches. 




Manchu- 
ria. 


Smyrna. 


Manchu- 
ria. 


Smyrna. 


Manchu- 
ria. 


Smyrna. 




42 
122 
2.9 


46 
282 
6.1 


87 
234 

2.7 


80 
361 

4.5 


179 
236 
1.3 


190 




446 




2.3 







i The selection of Manchuria was made for its low-tillering habit, and it is not typical of the Manchuria 
variety as commonly grown. 

The response to geographical location is a disturbance sufficient to 
vitiate all close distinction. Even the groups are often reversed. 
For instance, when summarized, a large number of selections of 
6-rowed barley at St. Paul averaged 2.6 culms per plant, while at 
Chico the same selections averaged but 1.5. The 2-rowed group, on 
the contrary, averaged but 4.2 culms at St. Paul, while at Chico it 
averaged 5.8. The Smyrna, however, stood near the top in both 
places, showing that in extreme cases the effect of environment does 
not conceal the character. 

LEAF CHARACTERS. 

The leaves of mature barley plants present quite a variety of 
aspects which are, as a whole, hard to record. Most of them are 
mass effects, and hence treacherous, because of the optical differences 
due to the angle of observation with reference to the light. This 
investigation is concerned with four points of variance — the color, 
the width, the length, and the number of leaves. 



COLOR OF LEAVES. 



A very casual observation shows a considerable difference in the 
color of leaves, but there are so many difficulties in their valuation 
that the writer is unprepared to discuss their separation at this time. 



14 



BULLETIN 137, U. S. DEPAETMENT OF AGRICULTURE. 



WIDTH AND LENGTH OF LEAVES. 

Any study of leaf dimensions must be statistical and therefore 
difficult to report briefly. The obstacles to the use of such measure- 
ments are twofold: The leaf varies with its nourishment and with 
its exposure, and it is often damaged by the wind. In a study of 
mature plants, the second leaf from the top being used in all cases, 
the normal variation was found to be considerable. For instance, 
at the same place in the same season the leaves of border plants were 
from 1 to 2 mm. greater in width than those from the interior of the 
plat, and the length of the leaves of such plants was from 2 to 3 cm. 
greater. In Princess, one of the least variable varieties, the average 
size of the leaves of the border plants was 13.7 mm. by 24 cm., and 
of the interior plants 12.7 mm. by 23 cm. 

To be usable in breeding, a note must be reasonably easy to obtain. 
To test the usefulness of this character, the first 25 of the 100 meas- 
urements of each selection were tabulated, as shown in Table III. 
With width of leaf, the experimental error is small, as width can be 
determined quite accurately and the broadest part of the leaf is 
seldom damaged. If the figures, then, are conclusive mathematically, 
the method is practical. The probable error in the 25 measurements of 
Princess is ±1.2. It thus fails to separate this variety dependably 
from Kitzing and Proskowetz, its nearest relatives, or from the selec- 
tion of deficiens, or Odessa. (See Table III.) From the rest,' how- 
ever, the separation is clear enough to be significant. With the two 
selections of Oderbrucker, the separation is sufficient to establish a 
difference. In this case the two are closely related and the note 
becomes serviceable. As a rule, the width of leaf is seldom a suffi- 
cient basis for separation in closely related strains. Fortunately, 
such differences are seldom unaccompanied by other points of va- 
riance, and it is often the sum of several differences that serves to 
distinguish individual strains. 



Table III. — Greatest, least, and average width and length of 25 lea res in each 
of 13 selections of hurley grown at 8t. Paul, Minn., in 1911. 



Pedigreed selection from— 


Leaf width. 


Leaf length. 


Greatest. 


Least. 


Average. 


Greatest. 


Least. 


Average. 




Mm. 
15.0 
15.5 
16.0 
17.5 
20.0 
22.0 
15.5 
20.0 
20.0 
20.0 
15.0 
22.0 
16.0 


Mm. 
12.5 
11.0 
12.5 
14.0 
14.0 
15.0 
12.5 
16.5 
16.5 
15.5 
11.0 
17.0 
11.0 


Mm. 
13.2 
12.7 
13.7 
15.5 
16.7 
IS. 7 
14.3 
18.5 
18.3 
17.8 
13.7 
18.7 
13.0 


Cm. 
28 
28 
32 
23 
27 
28 
26 
26 
26 
2.5 
22 
25 
28 


Cm. 
20.0 
20.0 
26.0 
17.0 
18.0 
20.0 
18.0 
18.0 
19.5 
20.0 
14.0 
20.0 
23.0 


Cm. 
23.5 




23.7 




28.7 




19.2 




22.8 




24.3 




22.5 




22.6 




22.9 




22.8 




17.9 




22.0 




25.5 







DISTINCTIONS IN CULTIVATED BAKLEYS. 



15 



In length of leaf, the method is much less promising. Not only 
is the probable error greater, but the measurement is unsatisfactory. 
The leaves become so broken by whipping in the wind that speci- 
mens which are entire at the tip are seldom found. An effort was 




Fig. 8. 



6 7 

-Composite curve showing the width of leaves in millimeters in eight selections of 

barley. 



made to overcome this difficulty by choosing an earlier stage of 
development and thus utilizing the better protected leaves nearer 
the ground. Although the extreme tendencies were not yet devel- 
oped, the second leaf from the seedling was found to offer fewer 
experimental difficulties. Such leaves were entire and the length 







































/SO 




































//O 
JOO 
30 
SO 
70 
60 
SO 
40 
30 
SO 
/O 

o 



























































































































































































































































































































































































































/O // J2 /3 /+ 



Fig. 9. — Composite curve showiDg the length of leaves in centimeters in six selections of 

barley. 

measurements accurate, but even then the width was much less 
variable than the length. All measurements, consisting of 100 leaves 
of each strain, showed a sharp curve in width, but a flat one in 
length, the latter sometimes having two summits. Composite curves 
are shown in figures 8 and 9. 



16 



BULLETIN 137, U. S. DEPARTMENT OP AGRICULTURE. 



The summary of leaf measurements of 316 pedigreed selections 
in Table IV shows that the common taxonomic groups, based upon 
spike characters, are correlated in the nature of their leaf growth. 

Table IV. — Summary of measurements of the width and length of barley leaves 
made at St. Paul, Mmn., in 1911, arranged according to the common taxo- 
nomic groups. 



Group. 


Number 

of 
strains. 


Leaf width. 


* Leaf length. 


Greatest. 


Least. 


Average. 


Greatest. 


Least. 


Average. 


Hordeum sativum ereetum 

Hordeum sativum nutans: 


11 

67 

18 

49 
85 

34 

23 
29 


Mm. 
17 

14 
18 

18 
20 

19 
19 
19 


Mm. 
13 

9 
10 

13 
15 

14 
13 
10 


Mm. 
14.0 

11.4 
13.6 

16.1 
17.7 

16.8 
17.0 
15.4 


Cm. 
26 

27 
28 

25 
26 

25 
27 
26 


Cm. 
22 

20 
20 

20 
22 

21 
22 
19 


Cm. 
23.9 

23.0 


Short-haired 


24.2 


Hordeum sativum vulgare: 
Manchuria types — 

Long-haired 


22.6 


Short-haired, white 

Short-haired, blue 


23.7 
23.3 


Russian types. 

Hordeum sativum hexastichum . 


23.7 
22.2 



NUMBER OF LEAVES. 

The number of leaves, excluding, of course, those formed before 
the appearance of the shoots, is the same note as the number of elon- 
gated internodes in the culm. The number of leaves above the basal 
rosette is a variable, but at the same time rarely a useful distinction 
in breeding. Strains may be found which are" very different, but 
usually they are not closely related. Thus, in the variety Hannchen 
the number often drops to three and seldom goes above five. In the 
selection of Hordeum sativum hexastichum the number rarely falls 
as low as five and is usually six or seven. This distinction, however, 
is not necessary to separate these forms. In each of several hundred 
Manchuria selections the number of leaves per culm fell upon either 
four or five, giving no opportunity for separation. 

THE DENSITY OF THE SPIKE. 

The writer is inclined to place even more importance upon the 
density of the spike than has been the tendency of many barley 
breeders. Aside from its finer distinctions, some of the effects at- 
tributed to other characters are in reality due to the length of the 
internode of the rachis. Most investigators have attributed the dif- 
ference between Hordeum sativum vulgare (tetrastichum) and Hor- 
deum sativum hexastichum to a difference in fertility. They have 
considered that in Hordeum sativum vulgare the side florets are more 
reduced than in Hordeum sativum hexastichum. .This supposition is 
not borne out by the facts. In the Hordeum sativum hexastichum the 
central row is as favored in nutrition as it is in the Hordeum sativum 



DISTINCTIONS IN CULTIVATED BARLEYS. 17 

vulgare. This is easily demonstrated by weighing kernels from side 
and central spikelets. In the Hordeum sativum vulgare the lateral 
kernels, compared with the central ones, are actually greater in rela- 
tive weight than is the case in the Hordeum sativum hexastichum. 

Differences other than density are likely to be due to the nature 
of the attachment of the lateral spikelets. Systematists describe the 
barley spikelets as sessile. This is true in most cases, but it ap- 
proaches an exception in Hordeum sativum hexastichum. In this 
group the central spikelets are sessile as usual, but the lateral ones 
either possess an elongation of the base of the flowering glumes or 
else are pedicellate. Among the barleys collected by the writer is a 
Greek form in which the lateral spikelets are elevated upon a pedicel 
that is over one-half as long as the length of the rachis internode 
itself. This pedicel is jointed both at its attachment to the rachis 
and at its attachment to the floret. It is the longer attachment of 
the lateral spikelets that allows the characteristic radial arrangement 
of Hordeum sativum hexastichum. Density is, however, a parallel 
factor. The compactness of the spike forces the kernels to assume 
certain relations. Both in Hordeum sativum hexastichum and in 
Hordeum sativum erectum, the kernels are placed at a much wider 
angle with reference to the rachis than in Hordeum sativum vulgare 
and Hordeum sativum nutans. The Swedish Plant-Breeding Associ- 
ation at Svalof has considered the angle of the inclination of the 
kernels as one of the more important of their notes. It is the opinion 
of the writer, however, that, with rare exceptions, it will vary di- 
rectly with the density, and is therefore superfluous if the latter 
measurements be taken. 

In breeding, density has not been utilized as fully as its value 
seems to warrant. Voss (25), Kornicke (15), and Atterberg (2), 
have used it in group classification, and Atterberg, Blaringhem (8), 
and the breeders at the Svalof station have used it in studies of 
variation and purity, but in the opinion of the writer its possibilities 
in the isolation of types and in the identification of strains have been 
far from exhausted. 

In the years from 1909 to 1913 a close study of density was made, 
both upon general farms and in experiment-station nurseries. In 
this study, 100 spikes of each variety were taken without other 
choice than that they were not diseased or dwarfed. On each of 
these spikes 10 internodes of the rachis were measured ; that is, the 
distance was between six spikelets on one side of the rachis. From 
these measurements the number of internodes per decimeter was 
computed and this number taken as the unit of density. The for- 
mula was then D=1,000^~L, where L was the length in millimeters 
of 10 internodes of the rachis. 
52783°— Bull. 137 3 



18 



BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 




22 23 24 2S 26 27 23 23 30 31 



32 33 



Fig. 10. — Curve showing the density (num- 
ber of internodes in 1 decimeter) of 100 
spikes of Manchuria bailey from a field 
near Excelsior, Minn. 



The use of this formula, while it makes the statement of density 
more definite, disturbs the natural curve of the measurements to 
some extent. In all densities below 31 the tendency is to condense 

the grouping; above that fig- 
ure the opposite is true. The 
worst effect — that of bunching 
the figures when two-length 
measurements fall upon the 
same density — was avoided by 
the use of fractions. None of 
the curves have been smoothed, 
however, and it will be noticed 
that those of the greater den- 
sities, especially, are slightly 
rough. This roughness is more mathematical than real, but it 
seemed more desirable to present the figures as they were than to 
make them still more artificial by smoothing them. 

In a pedigreed strain the curve 
of density is normally sharp ; with 
a single summit. If the seeding 
is not pure, or if the heads from 
two plats become mixed, the curve 
is flattened and is characterized 
by more than one summit. Al- 
though included for another rea- 
son, the normal curve of a pedi- 
greed barley is well illustrated in 
figure 12. When this is compared 
with the curve of the field sample 
of Manchuria shown in figure 10, 
the significance of density is read- 
ily appreciated, especially when it 
is remembered that the Manchuria 
is what is known as a variety and 
contains no types that merge into 
such other 6-rowed varieties as 
Bay Brewing or Odessa. 

That density of selections is an 
accurate and comparable note in a 
nursery where the object is to 

obtain like conditions for all selections is shown in figure 11. The 
Sandrel was included twice in the 1913 planting. The beds were 
separated by such a distance as to represent the extremes of soil 
variation in the nursery. The difference in density is very slight. 



40 



\ 



to 









'l 












/ 


/ 1 

/ 1 
/ ' 












/ 
/ 
/ 


\ I 










1 1 


/ 
/ 
/ 
I 












I 1 

I 1 
I 1 
ll 

'/ 
/ 

1 






v 

\\ 

I \ 

\\ 


^ 





23 24 



2S 26 27 23 29 



SO 3/ 



Pig. 11. — Curves showing the density of 
100 spikes from two plats of Sandrel 
(No. 35) barley planted in different 
parts of the 1913 nursery at St. Paul, 
Minn. 



DISTINCTIONS IN CULTIVATED BARLEYS. 



19 



£ 30 
Uj20 



to 













1 


\ 




















/ 


\ 
i 




















J 
1 


\ 




















1 


\ 




















1 


\ 




















I 


\ 














1 






1 
1 
1 
1 


\ 


\ 
\ 


















! 




\ 












1 




1/ 






\ 










I 


' 




l\ 






\ 










N 






1 
















1 
pi 




?'l 




\ 












# P\ 








N 








^-f 1 








N. 



£'J 



24 25 26 27 2a 23 30 

&£rA/s-/7-y 



3/ 32 33 



Fig. 12. — Curves showing the density of 
100 spikes from two selections of Man- 
churia barley grown at St. Paul, Minn., 
in 1913. 



The summits of the curves are separated by only one unit of density, 
but even this is seen to be too great when the entire curves are con- 
sidered. Although the second summit is on 27, there are 46 spikes 
whose density is less than that number and only 12 whose density is 
greater. The actual separation 
is nearer five-tenths of a unit. 
The degree of separation af- 
forded b}^ a difference of only 
two internodes to the decimeter 
is shown in figure 12. These 
are two selections of Manchu- 
ria barley taken at random 
from Table V. By chance, 
they are somewhat more ideal 
than the average strain in the 
same table. A difference of 
only two units in density, when 
taken alone, is perhaps too 
slight a basis upon which to 
separate strains, yet, as is 
shown in the figure, the field 
of actual merging is very 
small. 

The value of this character in the nursery is shown in figure 13. 
These barleys are all closely related pedigreed strains of Manchuria. 
Most of them were from head selections made upon farms in south- 
eastern Minnesota. The curve represents the summits of the curves 

of densities of the 
individual selec- 
tions. The varia- 
tion is consider- 
able and is suffi- 
cient to establish 
some differences of 
itself. It is, how- 
ever, only when 
several characters 
are compared that 
the full value of 
any note is appar- 
ent. For this pur- 
pose, the date of the emergence of the awn is placed also in figure 13. 
As they are in no way parallel, the combination of the two curves 
more than doubles the value of each. It will be noticed that Nos. 3, 
6, and 55 are suspiciously similar, the density and the date of emer- 



M 


to 

29 

:e 

27 

26 
25 
24 
<S3 




























/ 


^ 


X 






























\ 




















/ 






s 


f 


\ 


i 










/ 


\ 








/ 










\ 






/ 


s 


/ 


\ 




/ 


\ 


/ 










\ 






/ 


s 


t 




^N 


' 


\ 


I 










\ 




S 




























B 

5 




























































































3/ 

<tl 27 
0?6 




































































x" 


\ 
























\ 


I 




\ 






^— - 


— -* 


\ 














\ 






\ 




/ 






\ 










/ 




\ 








-- 


/ 






\ 






/ 


\ 


/ 




\ 


/ 














\ 




/ 


\ 


/ 



7S~ 77 33 36 S3 /03 /OO /<?/ .57 



55 67 57 /02 



55LEC7/0/V /VC/A/S5/?5 OF Srf?A/A/£: 

Fig. 13. — Curves showing the average density and the date 
of emergence of the awns in 16 selections of Manchuria 
barley grown at St. Paul, Minn., in 1913. 



20 



BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 



w 


2 

'30 
21 

2a 
2 7 
26 
25 
2* 
23 
22 
21 

[so 














































1 

HI III 

in 




























































































































































F 
























\ 
























^ 






























































































































































































X 




















J 




$30 
















f 


\ 


/ 




Uia9 


—\ 














/ 


s 


/ 
















/ 








26 






















































































































22 


























9 3 


f 9 

St 


7 3 

-ire 


1 s 

T/OAl 


3 :, 

/VL 


s / 

■MB. 


1 3 
"5- 


or 


f :■ 

SI/7, 


i 3 
J/A-JJ 


_ a 



gence of the awns of the three being identical. The records show 
that the emergence was also on the same date the previous year. 
No. 55 is proved to be distinct by the nature of the rachilla, but the 
date of heading, time of stooling, etc., are parallel in Nos. 3 and 6, 

and there is little doubt that they 
are identical. 

While not pertinent to this 
phase of the discussion, the 
curve of density and the curve of 
emergence of beards are almost 
opposite in the Manchuria bar- 
ley. In other words, there seems 
to be a direct correlation be- 
tween density and earliness. In 
figure 14, in which are assembled 
a number of other types of 6- 
rowed barleys that are for the 
most part not closely related, 
this is not true. 

The first five selections, the 
densities of which are shown in 
figure 14, are from a commercial 
variety known as Odessa. This 
so-called variety seems to be a 
loose assemblage of widely varying types, which are, however, ones 
not common in other 6-rowed barleys. The component strains are 
not nearly as closely related as are those of the Manchuria. That 
this variety itself is of hybrid origin or that there has been crossing 
between its members 
is indicated in figure 
15. This selection, the 
most dense of those % x 
made from the Odessa 
variety, proved un- 
stable. The number 
of plants bearing 
dense heads was 71, 
as opposed to 16 for 
the looser ones. 

While a character 
need not be invariable 
under all conditions in 
order to be useful, a test was made to discover the effect of soil and 
climate on density of spike. Six selections were planted at St. Paul, 
Minn., at Chico, Cal., and at Aberdeen, Idaho. At Aberdeen they 
were grown both under irrigation and upon dry land. The measure- 



Fig. 14. — Curves showing the average 
density and the date of emergence of 
the awns in 12 miscellaneous selections 
of barley grown at St. Paul, Minn., in 
1913. 



fl 30 

\ 

X 
«> 

\so 

\ 
\ 


















































































/ 


\ 
































/ 


/ 




\ 
























^S 



















Fig. 15. — Curve showing 
Odessa (No. 9) barley 
1913. 



the density of 134 spikes 
grown at St. Paul, Minn., 



of 



DISTINCTIONS IN CULTIVATED BAELEYS. 



21 



merits at St. Paul and at Aberdeen were made by the writer, while 
those at Chico were made by Mr. E. L. Adams. The result is shown 
in figure 16. As a whole the variations were parallel, Nos. 6 and 35 
being strikingly so. The four less dense selections showed an extreme 
variation of only three units, while the two dense selections varied 
much more. In No. 32 this was due in part to poorly developed 
heads; at St. Paul, particularly, its spikes were so short that it was 
impossible to find many in which five successive nodes bore fertile 
florets. The effect of sterility is to lengthen the internode of the 
rachis. All types were most dense at Chico and least dense at St. 
Paul. The effect of irrigation as shown 
at Aberdeen was very slight, especially 
when compared with the effect of the 
combined factors of geographical loca- 
tion. 

The character of the curves was in- 
fluenced even less than their relative 
density. Table V shows the distribu- 
tion into their various densities of 100 
spikes from each of 59 plats of barley. 
By referring to Table V it will be seen 
that some selections always present a much 
sharper' curve than others, and thus af- 
ford opportunity for varietal distinc- 
tions in the distribution of the measure- 
ments. Avoiding the extreme examples, 
it will be noted that the spike of No. 30, 
for instance, which has already been 
condensed three or four units by the use 
of the formula for density, is still less 
compact than No. 35, which by the same operation has been made 
to appear slightly less compact than it really is. At St. Paul, No. 35 
has a total of 85 per cent of its spikes within three units in one in- 
stance and 91 per cent in another, while No. 30 has but 82 per cent 
within this limit. At Aberdeen, under irrigation, No. 35 has a total 
of 91 per cent of its spikes within three units, while No. 30 has but 
78 per cent ; upon the dry farm at the same place, No. 35 has a total 
of 81 per cent of its spikes within three units, while No. 30 has but 
77 per cent ; and at Chico, No. 35 has 94 per cent of its spikes within 
three units, while No. 30 has 91 per cent. 




Fig. 16. — Curves showing the 
average density of six selections 
of barley grown at Chico, Cal., 
at St. Paul, Minn., and on irri- 
gated and unirrigated land at 
Aberdeen, Idaho. 



22 



BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 



Table V. — Distribution into their various densities of 100 spikes from each of 

59 plats of baric)/.' 



Place and name. 


Stock 
No. 


Row 

No. 


Number of internodes in one decimeter. 


21 
14 


22 

1 
16 

3 

2 
6 

1 

1 

3 

3 


i 

1 

1 

LI 

35 

8 

1 

5 
15 

6 

4 

1 
1 

S 
3 


24 

33 

■■' 

3 
11 

2 

1 

11 

37 
28 

23 

15 

16 

26 

1.-, 
13 

3 
3 
1 
2 

20 
2 
- 


.V 
15 

27 
1 

i 

15 

-■;: 

i- 
s 

12 
13 

35 

39 
6 

r, 

2 

1 

54 
8 

45 

37 
II 
3 

41 

44 

15 
26 
33 

12 


26 

6 

21 

::: 

4 

10 

23 

-1 

34 


27 

1 
3! 

2' 
30 

i; 
i 

!! 
19 

3 
11 

1 


! 

: 
t 

33 
1 
3 
8 

3. 

1 i 
1 

is 
4 
9 

11 

! ! 
5 
1 

14 
K 
34 
37 
17 

12 

1 

2 
2 

26 
2 
1 

27 

12 
9 
4 

13 

37 

19 

31 

8 
1 

21 
30 
20 
13 

1 


2: 

: 

22 

20 
1 

1 
33 
36 

17 
21 
2 
4 
6 
2 
1 
1 

9 
18 

31 
21 
H 

8 

6 
1 
1 

21 

12 

10 

5 
1 
13 

30 


3, 

31 
1 

16 
10 


1 

3132 
1 

27 9 
3 
31 24 


2 
11 

22 

1 
10 

1 

1 

21 

6 
2 
1 

1 

10 


3-1 

7 
5 

20 

9 
3 

1 

1 
16 

11 

1 
1 
3 


35 36 

2130 
1 1 

l 
i 


37 
36 


3,, 

2 


3! 
2 

3 

10 

12 
18 

21 

11 


li 
-• 

21 
IS 

9 

2! 

2S 
21 


41 

13 

22 

1 
6 

2 

9 


12 
1 

13 
34 

1 



4 
13 


43 

10 


44 
10 


5 
1 


46 


St. Paul, Minn.: 


11 
34 
13 
35 
73 

9 
32 
24 
75 
77 
99 
96 
89 
35 
94 
72 
103 
100 

8 
97 
60 
23 
101 
51 
102 

5 

3 
31 
19 

6 
93 
55 
30 
67 
56 
57 
54 

( 2 ) 
( 2 ) 
( 2 ) 
( 2 ) 

30 
32 
13 
19 
35 
6 

' 6 
32 
13 
19 
30 
35 
6 
35 
30 
19 
32 
13 


17 
29 
31 
33 
67 
23 
25 
32 
69 
71 
96 
93 
83 
87 
89 
66 
100 
97 
41 
94 
54 
30 
98 
45 
99 
39 
91 
21 
22 
14 
88 
49 
42 
61 
50 
51 
52 

A 
B 
C 
D 

25 
28 
31 
15 
32 
14 

79 

100 

103 

26 

37 

74 

379 

374 

337 

326 

400 

403 








Eagle 






















9 


1 
.... 




Oderbrucker 






32 '3. 3 

26 5 3 
41 2fi Q 








Lake City 




Silver King 






34 12 
ox m 
34 32 

36 15 

11 2 

1 
27,31 
2J34 
219 

3 31 


1 

2 

2 
4 
10 

7 
28 

2 
19 
6 

13 

7 
1 

3 

6 

1 


11 

1 

10 

1 

28 
1 

3 

10 

2 

10 

34 

1 
1 

21 

3 
1 
6 

21 


27 

3 

1 
31 

2 

6 

2 

3:1 

6 

s 

10 

j 

15 


















Luth 










13 4 

I 












Do 




















Luth.. 


10 

25 
25 

24 

in 
11 
23 

21) 
1 

19 

31.1 
32 
21 


2 
2 

44 

13 

13 
1 

311 

12 

17 
12 

17 
25 
29 
30 

24 

35 

37 

1 

10 
5 
31 
11 
34 




Meyer 












23 3* 


24 

3 
20 


4 

7 
8 




Fcatherston 


• 

9 
14 


1 
1 










Featherston 








Minnesota No. 105 




Luth 








Excelsior, Minn.: 




Do 




Do 




Do 




Chico, Cal.: 




Mariout 


.. u 


,1 


Eagle 


3 

34 
2 


7 
1! 
1 

24 

1 
9 




Svanhals 


1213 








1 


1 
4 




Featherston 


IS 
11 

20 

47 
is 
34 
3 

5 


1 

0, 
30 

23 
3 
2! 

12 




Aberdeen, Idaho: 

Featherston 








Eagle 




Svanhals 


2 4 

5 6 

2,4 


2312 






18 

10 


14 

•J 


















12 so 




Svanhals 












Eagle 






1 







1 Featherston, Luth, and Meyer are all Manchuria or Oderbrucker barleys, named from the farms upon 
which the selections were made". Measurements of 134 instead of 100 spikes are given in Odessa No. 9, -which 
broke up into two types. The Excelsior barleys were from general fields, three of which were unpediTeed. 
At Aberdeen, rows 26 to 103 were irrigated, while rows 326 to 403 were grown upon dry land. The irregu- 
larity in Mariout is largely due to imperfect spikes. 

a Field. 



DISTINCTIONS IN CULTIVATED BARLEYS. 23 

FERTILITY. 

The variation in fertility is the most evident and the most vital of 
all the modifications that occur in barley. At each node of the 
rachis a group of three single-flowered spikelets is produced. In 
the 6-rowed barleys, each of these develops a separate kernel. As 
the groups of spikelets are placed alternately on opposite sides of 
the rachis the result is six columns of kernels from the base to the 
tip of the spike. In the 2-rowed barleys, only the central spikelet 
at each node is fertile, and therefore there are but two columns of 
grains. This reduction does not take place by the elimination of 
the outer spikelets but by their sterility. The median floret of each 
set of three accomplishes its normal development, while on either 
side are the small, undeveloped, infertile florets. However, the 
sexual organs have not disappeared. The three stamens reach an 
appreciable size and the ovary, though rudimentary in some ways, 
persists even to the plumose stigma. In one group of the 2-rowed 
barleys there is a still further modification of the lateral florets. In 
Abyssinian barleys there is a considerable number of forms in which 
the lateral spikelets are rudimentary; that is, they no longer contain 
even infertile flowers, the whole spikelet being reduced to structures 
that are little more than hairlike. 

In the experience of the writer these well-known taxonomic divi- 
sions have proved entirely stable. The observations have included 
hundreds of varieties, and these varieties have been grown under 
such varying conditions as to stimulate monstrous developments in 
many structures, but in no case has there been indication of bridging 
over these separations. It is the opinion of the writer that the numer- 
ous instances of exceptions recorded have been misinterpreted. The 
one cited by Kornicke (15) was most probably a cross, as the varia- 
tion of the progeny was such as is always secured by hybridization. 
The more common exceptions usually described are the'occurrence of 
3-rowed and 8-rowed freaks, and 2-rowed barleys in which some of 
the lateral florets are fertile. All three exceptions are probably due 
to the formation of adventitious spikelets. Such spikelets are com- 
mon, and if several of them occur along one side of the rachis of a 2- 
rowed barley the result is a 3-rowed spike. If a duplication of the 
groups of spikelets at the nodes of one side of the rachis occurs in a 
6-rowed barley, the result is nine rows, which, if imperfect in any 
way, are easily mistaken for eight. It is entirely possible that florets 
of lateral spikelets of 2-rowed varieties are sometimes fertile, but in 
practically all of the numerous cases that have been noted by the 
writer a close inspection of such grains has shown them to be adven- 
titious, with the sterile floret also present. 



24 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

Aside from the observations upon established forms, it has been 
the fortune of the writer to isolate a number of which there seem 
to be no published descriptions. These all came from Abyssinian 
barleys, and, as the work is not yet completed, only a general indi- 
cation of the results need be given here. The group of 2-rowed 
barleys with rudimentary florets seems much larger than has been 
previously thought. 'They vary from the wide zeocrithonlike types 
to narrow nutanslike forms and through a series of colors and com- 
binations of colors. In barleys received from the same region there 
is a group with a curious irregular, yet heritable, habit of floret 
abortion. In the ripened spike the spikelets are normal at the base 
and for a varying distance toward the tip. The upper portion 
usually reduces suddenly to a 2-rowed form. In this case the lateral 
spikelets are not merely sterile, but are reduced to only the outer 
glumes and the rachilla, the floret having, disappeared entirely. The 
spikes are found to present these modifications even when the head 
first emerges from the boot. The actual time of the reduction has 
not been determined, but it is so early that no scar is present, indi- 
cating that the floret never started to develop. 

THE EMPTY, OR OUTER, GLUMES. 

The outer glumes present but two phases. They are usually nar- 
rowly lanceolate, but in rare forms are ovate lanceolate. In the 
latter case they generally bear moderately long awns. A few inter- 
mediates are formed by combinations in which only certain ones 
instead of all the normal outer glumes are replaced by ovate-lanceo- 
late ones. In this investigation, while numerous ovate-lanceolate 
selections have been made, there has been nothing added to the 
information already at hand. 

THE FLOWERING GLUMES. 

Two of the variable features of the flowering glume are treated 
elsewhere. The toothing of the nerves is considered with the rest 
of the Svalof system under a later heading. The color of the glumes 
is taken up with the color of the other plant organs in the general 
discussion of pigmentation. Most of the remaining variable points 
of structure in the flowering glume are to be found in its terminal 
appendages, which are usually awns, but may be trifurcate hoods, 
in the nature of its base, and in its adherence or nonadherence to the 
pericarp. 

AWNS. 

The dimensions of the awns are naturally their most apparent 
variable features. There are marked varietal differences in both 
length and breadth of awns, but, unfortunately, they are so corre- 



DISTINCTIONS IN" CULTIVATED BARLEYS. 25 

lated with the taxonomic groups as to make them of slight use in 
separating nearly related strains. All the Hanna barleys have long, 
narrow awns; the zeocrithon and hexastichu?n forms have short, 
rather broad awns and the naked barleys excessively broad ones. 
In the Manchuria group there is some suggestive variation, but it 
needs the support of other variants to become convincing. 

There is, in addition to these rather narrow variations, a still 
greater difference in length of awn. In these cases an abrupt and 
conspicuous reduction takes place. There are botanical varieties 
characterized by very short awns and others in which the glume is 
merely pointed. Derr (12) secured such a form through crossing. 
Such variations make a very decided separation from their long- 
awned relatives. 

The toothing of the awn is subject to many variations, some of 
which are constant. The distinctions are often merely those of degree. 
There are forms, especially in the hexastichum and zeocrithon groups, 
in which the toothing is very profuse and the individual teeth very 
large. These characters are constant and are inherited, with no more 
tendency to variation than are other vegetative characters. In the 
Mancliuria-Oderbrucker barley the teeth are numerous, but only 
average in size, being much smaller than the ones referred to above. 
The 2-rowed barleys of the Hanna type have fewer and very much 
smaller teeth than the Manchuria. In still other barleys the awns 
are smooth. In 1910 the writer isolated from a mixed Hanna barley 
a form in which the awn was smooth, except for a few small teeth at 
the tip. In 1911 two plants were secured from an English importa- 
tion of a seldom-cultivated botanical variety in which the awns are 
absolutely smooth. Hybrids of this selection upon Manchuria and 
Bay Brewing sorts show the toothing to be dominant over the absence 
of teeth. In the second generation smooth awns again appeared. 
Regel (22) and others have reported a considerable number of such 
barleys. 

Although it seems not to have been used by systematists, the rigid- 
ity of the awn has been found to be serviceable in varietal descrip- 
tions. From most barleys it is broken rather easily in thrashing, 
but there are some which will not thrash clean, no matter how much 
effort be expended. This character is commonly recognized in the 
California barley, "but exists in Mariout, in some of the selections 
from Odessa, and in numerous others as well. These varieties have 
been grown at a large number of points and show no inconstancy in 
this character. 

There is also a difference in the persistence of the awns. There are 
a few varieties that are almost deciduous. The Primus, for instance, 
has been observed in a great variety of locations, and it always drops 
a large percentage of its awns as it ripens. The loss of the awn in 



26 BULLETIN 137, U. S. DEPARTMENT OP AGRICULTURE. 

such varieties does not come about through the breaking of that 
organ, but by its being loosened from the glume. It is the tissues of 
the glume that give way, and lack of persistence is thus in reality a 
character of that organ. 

In the hooded barleys the awn of the flowering glume is replaced 
by a trifurcate appendage. This is of evident monstrous origin and 
is connected with the awned class by no true intermediates. The 
exact nature of the appendage is not clear. In structure the parts 
ti ppear to be the result of vegetative stimulation, and they are glume- 
like in appearance. The fact that they are three in number and that 
they bear rudimentary florets indicates that they are a partial repeti- 
tion of the spikelets of an internode, the leafy segments being the 
flowering glumes. The character is absolutely constant. 

THE BASE OF THE FLOWERING GLUME. 

The method of the attachment of the lemma, or flowering glume, 
to the rachis has been shown by Atterberg (1) to be a distinguishing 
mark between the erectum and nutans groups. In the nutans group 
the grain (and therefore the flowering glume) is attached by a very 
constricted band of tissue which, when separated, leaves the proximal 
extremity smooth. The surface is oblique to the long axis of the 
grain and presents a small horseshoe-shaped depression just above 
the line of attachment. In the erectum group there is more than one 
variation of form, but all are centered around an attachment to the 
rachis that is much broader than in nutans and the depression is 
absent. When the central nerve of the dorsal glume is not too large 
and continued too far through the base, a transverse crease is found 
just above the attachment. The 6-rowed barleys are separated by 
the same means. 

ADHERENCE OF THE FLOWERING GLUME TO THE PERICARP. 

The normal form of barley is one in which the glumes are grown 
fast to the pericarp. There are numerous varieties in which this 
union does not occur. These constitute our naked barleys. Both 
forms are absolutely stable. The character offers no opportunity for 
minor distinctions, unless it be in such cases as Princess, which the 
Swedish Plant-Breeding Association maintains has a low weight per 
bushel, owing to an abnormally loose attachment of the glumes. 

THE SVALOF CHARACTERS. 

I 

In 1889, Neergaard (19), of the Swedish Plant-Breeding Associa- 
tion at Svalof , announced the most important discovery in the classi- 
fication of the lesser groups of barley that has ever been brought to 
the attention of the world. Not only was it of exceptional intrinsic 
value, but it acted as a great stimulus in the study of elementary 



DISTINCTIONS IN CULTIVATED BARLE1S. 27 

forms and has been the cause of much of the progress that has been 
made in the isolation of biotypes. 

Neergaard's work was based upon the careful study of the spike. 
He discovered that two previously unobserved variants were de- 
pendable morphological distinctions. These were the nature of the 
covering of the basal bristle and the toothing of the inner pair of 
dorsal nerves. The basal bristle, which is the continuation of the 
rachilla of the spikelet, is clasped within the folds of the glumes 
and is carried with the kernel when it is removed from the spike in 
the process of thrashing. The bristle is covered in some cases with 
long, stiff hairs; in others, with short, curly ones. The inner pair 
of nerves upon the dorsal surface of the grain are in some cases pro- 
vided with numerous, small, translucent teeth; in others they are 
smooth. 

The use of these two new characters gave four separations in any 
group, i. e., long-haired bristle and nerves without teeth, long-haired 
bristle and nerves with teeth, short-haired bristle and nerves without 
teeth, and short-haired bristle and nerves with teeth. When these 
separations were applied to the larger groups, Hordeum sativum 
erectum, Hordeum sativum nutans, and Hordeum sativum vulgare 
(tetrastichum) , 12 smaller groups resulted. 

Although this new grouping was only a small part of the Svalof 
observations on barley, it soon became known as the Svalof system, 
due no doubt to its novelty. As a new departure it has been subject 
to much more controversy than have most of the older and univer- 
sally accepted taxonomic features. Several breeders, among whom 
Broili (10) is the most notable, have attacked the system and de- 
clared that, though the characters might be trustworthy at Svalof, 
when the plants were grown under other conditions they did not re- 
main constant. Tschermak (13, p. 286), Blaringhem (7), and others, 
have supported the investigators at Svalof in the matter of the basal 
bristle, but have not committed themselves so completely with ref- 
erence to the toothing of the nerves. Since the point of contention 
is the effect of soil and climate, observations in this country are of 
many times the natural value of those in Europe. The variation be- 
tween California and Minnesota or Idaho and Virginia represents a 
range that is impossible to a European breeder. 

Observations have been made upon some hundreds of selections 
representing all botanical groups. Very little variation was found 
in the nature of the rachilla. All observations tend to credit this 
character with as much stability as is usually found in taxonomic 
work. As would naturally be expected, the toothing of the dorsal 
nerves has been found to be more variable and more influenced by 
climate. The rachilla is the axis of the spikelet, a definite and vital 
portion of the fruiting body. The teeth on the dorsal nerves are of 



28 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

no vital significance, being mere manifestations of the epidermis. 
The writer feels that the Svalof position has here been injured by a 
defense that is too enthusiastic. The fact that variations may or 
may not occur in a strain is of little importance if the limits are de- 
finable. No doubt there is variation, and it is especially noticeable in 
the sparsely toothed varieties. A cactus under proper conditions 
will display leaves, yet no one will question the propriety of describ- 
ing the cacti as leafless plants. They never become foliage plants, 
and no more do we expect a smooth-nerved Hanna selection to show 
the strong toothing of the Manchuria. It may at times present a 
few scattering teeth, but it would never become even moderately 
strongly toothed, and certainly there are strongly toothed sorts that 
are never anything else. 

VARIATIONS IN THE KERNEL. 

The kernel itself varies in many ways. The more definite varia- 
tions not treated elsewhere are shape, dimensions, weight, and com- 
position. 

SHAPE OF KERNEL. 

The shape of kernel is well established as a group distinction and 
is often a varietal characteristic. The 6-rowed varieties are sharply 
set off from the 2-rowed ones by the twisting of the lateral kernels. 
Even the central kernel of the 6-rowed varieties, although it is not 
twisted as are the lateral ones, is still of a shape different from that 
of the 2-rowed sorts. In the 6-rowed varieties the greatest diameter 
is nearer the distal end of the grain, while in the 2-rowed ones it is 
nearer the proximal end. 

Within the groups the separations are naturally less marked. 
Certain Finnish and Russian barleys may readily be distinguished 
from the Manchuria because of their being less nearly oval in 
shape. The extremities of the grain are more pointed, giving a 
fusiform, or spindle-shaped, seed. The Goldthorpe barleys, espe- 
cially such extreme types as Standwell, are readily separated from 
the other 2-rowed forms. The Swedish Plant-Breeding Association 
reports that Hannchen and Princess can be readily distinguished in 
bulk samples by the shape of the kernel. Most of the distinctions, 
however, are so dependent upon the relative proportions of the grain 
that it is impossible to consider shape independent of dimensions. 

THE DIMENSIONS OF THE KERNEL. 

The barley kernel varies in length, width, and thickness. At times 
one or all of these may constitute a varietal character. No other bar- 
ley could be confused with the Smyrna. Its long grain is unique. 
It is also very doubtful whether a second strain could be found that 
possesses the unusual breadth of the Standwell. In all but these 



DISTINCTIONS IN CULTIVATED BARLEYS. 



29 



very extreme types the use of these variants must rest upon statis- 
tical methods. 

At any place, the product of a variety in the same season is suffi- 
ciently uniform to give a decided indication of the average size of 
the kernel with 100 measurements. The size of the kernel is, how- 
ever, but partially dependent on variety. Table VI gives a summary 
of measurements made upon samples of grain of three varieties of 
barley grown at various points in the United States. In this table 
the columns marked " Greatest " and " Least " have very little sig- 
nificance, but the averages are quite instructive. The variation is 
remarkably uniform. The length and the lateral and dorso-ventral 
diameters of Princess each differ about 0.5 of a millimeter in the 
averages, while the dimensions of Primus each vary 0.4 mm. and 
those of Chevalier II 0.2 mm. It does not necessarily follow that 
Princess is the most variable of the three. This variety was sub- 
jected to more extreme conditions than the other two, and in two 
locations the development was hardly normal. 



Table VI.- 



-Dimension measurements (in millimeters) of 100 kernels of each of 
three varieties of oarley. 



Variety and place of production. 



Length. 



Great- 
est. 



Least. 



Aver- 



Lateral diameter. 



Great- 



Least. 



Aver- 



Dorso-ventral diam- 
eter. 



Great- 
est. 



Least. 



Aver- 



Princess: 

Huntley, Mont, (irrigated) 

Huntley, Mont, (dry land) 

McPherson, Kans 

Plainfleld, Cal 

Morris, Minn 

Primus: 

Svalof , Sweden 

St. Paul, Minn 

Bonsall, Cal 

Amarillo, Tex 

Milwaukee, Wis 

Fort Atkinson, Wis 

Chevalier II: 

Warren, Minn 

Flandreau,N. Dak 

Erie, Pa 

Plainfleld. Cal 

St. Paul, Minn 

Milwaukee, Wis 



9.6 
10.2 
9.6 

10.1 
10.4 
9.8 
10.0 
10.5 
10.4 

10.0 
10.0 
9.8 
10.0 
10.2 
10.4 



9.0 
8.7 
8.8 
9.0 
8.7 

9.1 
8.7 
9.0 
8.9 
9.6 
9.0 

8.3 
9.0 

8.8 
8.2 
8.3 

8.4 



9.3 
9.2 
9.2 
9.5 
9.1 

9.6 
9.6 
9.5 
9.6 
9.9 
9.8 

9.4 
9.6 
9.4 
9.4 
9.5 
9.6 



3.3 
3.0 
3.1 
3.3 
3.0 

3.4 

3.4 
3.2 
2.9 
3.4 
3.4 

3.1 
3.1 
3.2 
3.3 
3.0 
3.2 



3.6 
3.2 
3.3 
3.7 
3.4 

3.8 
3.7 
3.6 
3.4 
3.8 
3.7 

3.6 
3.5 
3.6 
3.7 
3.5 
3.6 



2.2 
2.0 
2.2 
2.3 
2.0 

2.5 

2.5 
2.6 
2.2 
2.4 
2.4 

2.2 

2.2 
2.5 
2.5 
2.1 
2.3 



2.7 
2.2 
2.5 
2.6 
2.3 

2.9 

2.8 
2.8 
2.5 
2.6 
2.8 

2.6 

2.6 

2.8 
2.8 
2.6 
2.7 



Of the three measurements, that of length is obviously the most 
dependable. The actual variation is no greater, and since it is based 
upon a much larger figure it is relatively less. Also, the two diame- 
ters are more affected by ripening conditions than is the length and 
are therefore less serviceable for local distinctions. The length seems 
to be determined by varietal and climatic influences early in the life 
of the plant, while the diameters are dependent upon the quantity 
of starch infiltration at ripening time. This is well illustrated in 
the two samples of Princess from Huntley, Mont., one of which was 
grown by irrigation and one on dry land. .The length of the kernels 



30 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

in the two samples was practically identical, while the diameters 
showed the greatest variations found within a variety. 

The weakness of all grain measurements is not in the variation 
but in the fact that the interval between varieties is not great. The 
total range of averages is not large, and while many selections may 
be distinguished, a great many more must remain inseparable be- 
cause of identical cr nearly identical dimensions. 

WEIGHT OF THE KERNEL. 

The weight of 1,000 kernels is a determination that has been con- 
sidered indispensable in the appraisement of exhibition samples, 
and it is also a very useful record in plant breeding. From the 
nature of this factor it is to be expected that it will vary with con- 
ditions and culture, but usually the variations are more or less par- 
allel. In this investigation certain varieties have always been found 
relatively high and others relatively low in kernel weight, regardless 
of location or season. The character is, however, a varietal one and 
not often useful in separating related strains. 

COMPOSITION OF THE KERNEL. 

The varietal character of any barley, as far as composition is 
concerned, is subservient to climatic conditions. For example, if 
it is grown in California it will be much lower in nitrogen than if 
grown in Minnesota. The average differences in the composition 
of all varieties grown at two places is often greater than that be- 
tween the two most extreme varieties at either place. Despite this 
fact, there is an actual varietal tendency. The Svanhals is reported 
in Sweden to be relatively high in nitrogen for a 2-rowed barley, and 
it is also high in this country. Analyses of samples of California 
feed from many States in the West and in the Plains area showed 
that this variety was always lower in nitrogen than other 6-rowed 
forms. Le Clerc and Wahl (17) found that the average protein 
content for Bay Brewing from all points was 10.73 per cent, while 
for the ordinary 6-rowed variety it was 11.86 per cent. 

It is doubtful whether a factor with such wide and easily influ- 
enced limits can be made to be of assistance in the separation of 
strains, save in exceptional cases. It can, however, be used in the 
description of varieties, and may be of much importance in the 
selection of sorts adapted to satisfy market demands. 

PIGMENTATION. 

Color is one of the most easily determined characters of barley, 
but, unfortunately, it is also one of the most treacherous distinctions. 
The occurrence of pigments in certain cases and in certain tissues is 
undoubtedly hereditary and is transmitted unfailingly from genera- 



DISTINCTIONS IN CULTIVATED BARLEYS. 31 

tion to generation. In other cases the color appears intermittently 
or sporadically in strains and tissues ordinarily free from pigments. 
This erratic behavior, coupled with the fact that white, brown, 
black, violet, purple, amber, and blue-gray have been used in various 
classifications, led the writer to make a study of the pigmentation of 
barley. Since the colors in the seed seemed to be more numerous and 
less variable than in the other parts of the plant, the grain was used 
as the basis for the investigation. 

The technic was adapted from that used by Mann (18) in his 
identification and location of the pigments in the cowpea. The 
grains were first examined by sectioning them dry. This avoided 
any modification such as might easily come from the action of solv- 
ents in an embedding process, or even from water if a freezing 
method were used. The hand sections were equally as satisfactory 
as those made with a microtome, as the areas in question were readily 
defined and the colors more easily seen in moderately thick sections 
than in very thin ones. The reagents most extensively employed 
were caustic potash, hydrochloric acid, and chloral hydrate. The 
sections were placed dry upon a microscope slide underneath a seven- 
eighths-inch cover glass, held in place by a drop of paraffin on either 
side. The reagents were drawn beneath the cover glass by means of 
blotting paper and their action watched through the microscope. 
Two per cent solutions of the acid and of the alkali and a saturated 
aqueous solution of chloral hydrate were used in these tests. If the 
pigment showed no change within a few minutes, the reagents were 
allowed to remain upon the section for some hours. In such cases, 
larger pieces were also placed in small vials containing 15 per cent 
solutions and examined at the end of 24 hours. 

It soon became apparent that there were two pigments in barley. 
One was readily affected by the weak solutions, and from the nature 
of its reaction was undoubtedly anthocyanin, which occurs widely in 
the plant kingdom in both its red, or acid, and its blue, or alkaline, 
form. The other resisted even prolonged soaking in the more con- 
centrated solutions and was probably a melaninlike substance. 

The first varieties studied were those in which the adhering glumes 
were black. No change was effected by either the weak reagents or 
the prolonged soaking in concentrated solutions. The black did 
indeed become a brown, but this was most probably due to the dis- 
tention of the pigment-containing tissues attendant upon the absorp- 
tion of water. As a considerable number of varieties with black 
glumes were tested and as the results were uniformly the same, it 
would seem that a black or brown pigment in the glumes may be 
attributed to a melaninlike compound. 

A number of Abyssinian varieties with purple glumes were sec- 
tioned and treated with the reagents. The purple color responded 



32 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

tit once to weak solutions. It immediately became blue when treated 
with the alkali and became red again when the acid was applied. 
The chloral-hydrate test here and in all other instances was less 
definite than in the case with most anthocyanin deposits. Upon its 
application the red color faded very slowly, until the natural yellow 
of the glumes became apparent. The red immediately returned when 
acid was added. There is no reasonable doubt that the color in these 
barleys is due to anthocyanin. 

A naked barley with a violet or purple pericarp was examined. 
This color was also readily demonstrated to be anthocyanin. In this 
instance, as in some others, the pigment was found both in the peri- 
carp and in the aleurone layer. In the former tissue it was red and 
in the latter blue. When treated with acid the red was unchanged, 
of course, while the blue also became red, greatly intensifying the 
effect. 

In all barleys studied the anthocyanin was always red in the peri- 
carp and glumes and always blue in the aleurone layer. In other 
words, the resting condition of the protoplasm was alkaline, while 
the inert tissue seemed to be in an acid condition. 

A new form of naked barley isolated from an Abyssinian importa- 
tion gave striking testimony of the taxonomic value of the distinc- 
tion between the two pigments. This selection has a dense black 
pericarp. It was absolutely resistant to all concentrations of re- 
agents, showing the pigment to be melaninlike. As far as the writer 
can learn, there is no other naked barley of the nutans group in 
which this pigment occurs, and this botanical form has no published 
description. 

The last variety studied was Hordeum vulgare pallidum coerules- 
cens. This variety has the peculiar blue color well known upon the 
market in California!!, Chilean, and similar barleys. The color has 
been held to be variable by both grain dealers and scientists. Kegel 
explains its lack of stability by calling it a hybrid form. Examina- 
tion showed the color to be due to a deposit of anthocyanin in the 
aleurone layer. This layer was readily changed to red by the appli- 
cation of acid and was as readily made blue again by the use of alkali. 

The stability of this and other forms was studied in the fields. 
Anthocyanin seems likely to be found in any plant and in any part 
of the plant. It seems to appear abnormally in cases of malnutrition 
and is very likely to occur in conductive tissues that are ceasing to 
be functional. It has, however, a normal phase in the grain. In 
certain naked forms its stability is unquestioned, and, to the writer's 
mind, its variability in coerulescens has been overestimated. The 
hybrid theory of Kegel in regard to coerulescens becomes untenable 
when two pigments are admitted. If an intermediate, it could be 
so only between a white variety and a black one. This is evidently 



DISTINCTIONS IN CULTIVATED BARLEYS. 33 

impossible, because a cross between a form with a melaninlike pig- 
ment and one with no pigment could not result in one characterized 
by the production of anthocyanin. The widespread opinion of va- 
riability is possibly due to faulty observation. The deposit is in the 
aleurone layer, and the color is sometimes obscured by the glume. 
The weathering of this organ, especially in humid areas, greatly les- 
sens its transparency. The aleurone layer is covered by both peri- 
carp and hulls. The color must not only be pronounced to enable 
one to detect it from without, but the coverings must also be passably 
transparent. When ripening occurs in rainy weather this is not the 
case, and the hulls must be removed in order to make a trustworthy 
determination. Maltsters often speak of the blue grains that appear 
after steeping — that is, when the coverings have become trans- 
parent. 

There is undoubtedly a difference in the quantity of the pigment 
deposited from year to year. Part of this may be due to the condi- 
tions of growth and part to the conditions of ripening. This pig- 
ment, like melanin, is formed during the later stages of growth. It 
may be that an abbreviation of the ripening period, due to heat or 
drought, would result in a reduction of pigment. 

The inheritance of this character has been tested by observations 
upon several strains isolated from various barleys. These have been 
grown for several years and at a number of places, and in every in- 
stance the aleurone layer has retained a decided amount of blue 
color. The black colors have become more nearly brown in some 
places but have never disappeared. Blue-gray and violet-purple 
colors in naked barleys are due to blue anthocyanin in the aleurone 
layer combined with a pigment- free pericarp in the blue-gray and 
with a red anthocyanin deposit in the violet. Both are unquestion- 
ably inherited. 

Minor phases of anthocyanin formation are found in the foliage 
of the plant, in the nerves of the glume, and in the awn. A red 
foliage, although found more commonly in some forms than others, 
may ordinarily be disregarded. In most cases it indicates malnutri- 
tion of some sort. In the nerves of the dorsal flowering glume it may 
be more valuable as a distinction. A great many barleys show this 
character to some extent. Even the Hanna races possess violet or 
purple nerves just before ripening. None, however, develop the 
color to the degree that is attained by some of the Russian and Asi- 
atic forms. In the barley nursery there are several Russian selec- 
tions in which the stripes along the nerves are so broad that the 
grains are almost red. The same is true of the strain known as 
Kashgar, which was imported from the region of that name in India. 

With reference to the color of the awn, an apparent anomaly was 
noted in 1911. In a certain selection some spikes were observed in 



34 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

which each awn Avas marked with two parallel stripes of red extend- 
ing from its base to its tip, and other spikes in which the same stripes 
were deep purple. When examined in the laboratory, the color 
proved to be two bright-red stripes in the epidermis, below which 
were two chlorophyll-bearing parenchyma areas running the full 
length of the awn. As long as the chlorophyll was present the color 
effect was deep purple, but as soon as this disappeared it was light 
red. 

SUMMARY. 

While all lesser distinctions must be based upon the broader 
groups and no study of a cereal can omit its classification, the plant 
characters useful in taxonomic work and the ones most useful in 
plant breeding are far from being the same. Plant breeding is con- 
cerned with minute differences. The broad taxonomic divisions are 
serviceable only as groups. The problem of the nursery is not to 
separate a 6-rowed Manchuria from a 2-rowed Hanna barley, but 
to detect a variant in a plat of Manchuria. 

Strains are often shown to be distinct in early growth by their rate 
of development. All barleys rush through the early stages very 
rapidly, and a selection that is one or two days earlier than a second 
is very dissimilar in appearance on a given date. 

Leaf production is, in some ways, a varietal character. In some 
varieties the third leaf appears in three days after the second, while 
in others it occurs six days later. In the production of the fourth 
leaf even a greater range exists. 

In some strains the first tiller appears decidedly later than the 
fourth leaf. In others it appears earlier. In some the tillers are 
all produced within a short time; in others the process is extended 
over several days. 

The emergence of the awn is an extremely important note, as it 
occurs at a time in the life of the plant when such an observation is 
of great value. The development is usually normal at this time, as 
hot weather and drought have ordinarily not yet had any effect. 
The emergence of the awn has been found to be far more accurate 
and more easily obtained than the date of heading. The precocity 
of the strain at the time of the emergence of the awn is a heritable 
character. 

The date of ripening is, unfortunately, often influenced by season 
and, while a valuable character, is less dependable than the emergence 
of the awns. 

A comparison of the development during all stages serves to reveal 
many differences not apparent when each stage is taken separately. 

The length of the culm is of use as a local breeding note, but the 
variations are not parallel when strains are planted in totally dif- 



DISTINCTIONS IN CULTIVATED BARLEYS. 35 

ferent areas. The diameter of the culm is not serviceable, because 
nearly related barleys have culms of approximately the same size. 
The thickness of the walls of the culm is a note with a large experi- 
mental error and therefore of questionable utility. 

The degree of exsertion of the spike is sometimes a varietal char- 
acter but is not often useful. 

The number of culms per plant is to some extent a varietal char- 
acter, but selections are so affected by season and location that it is 
very difficult to use. The width of the leaves is useful in group 
distinctions and sometimes in varietal separations. The length of 
the leaves is much less dependable, and is serviceable only in rather 
extreme types. The number of leaves varies with the groups, but 
usually closely related strains possess approximately the same num- 
ber of leaves. 

The density of the spike may easily be made the basis of many 
separations. Often varieties that show no other differences are 
widely dissimilar in density. The density of a selection varies 
somewhat with season and location, but the mean is always sharply 
defined and the fluctuations more or less parallel. In some strains 
all spikes conform closely to the mean ; in others the range is greater. 
This seems to be a varietal character and is constant even when the 
plantings are made under widely varying climatic and soil conditions. 

The established taxonomic groups based on relative fertility were 
found to be invariable under all extremes of American climate. 

The natural varieties in the deftciens group of Abyssinian barleys 
seem more extensive than most classifications have indicated. From 
barleys of this same region a group with a peculiar habit of floret 
abortion has been isolated. 

The length and the width of awns vary, but they are so correlated 
with other taxonomic characters that they are seldom useful in close 
separations. 

The tenacity of the awn is frequently a varietal character unaf- 
fected by location or season. 

The character of the basal bristle has been found to be stable 
under American conditions. 

The toothing of the inner pair of dorsal nerves is much more 
variable, but the variation is usually within definable limits. 

The length of the kernel, while influenced by climate, is a varietal 
character. The lateral and dorsoventral diameters of the kernel are 
varietal characters to some degree, but they are so influenced by con- 
ditions of growth as to become confusing in most instances. 

The composition of the grain is a varietal character, but it is one 
dominated by climate. 

There are two coloring materials in barley : One, anthocyanin, is 
red in its acid and blue in its alkaline condition ; the other, a melanin- 



36 BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 

like compound, is black. The pigments may occur in the hulls, the 
pericarp, the aleurone layer, and occasionally in the starch endo- 
sperm. The resulting colors of the grain are quite complicated. 
White denotes the absence of all pigment; a heavy deposit of the 
melaninlike compound in the hulls results in black; a light deposit, 
brown. Anthocyanin in the hulls results in a light violet-red. In 
naked forms the melaninlike compound in the pericarp results in a 
black kernel ; anthocyanin produces a violet one. The acid condition 
of anthocyanin in the pericarp superimposed upon the alkaline con- 
dition in the aleurone layer gives the effect of a purple color, while 
a blue aleurone beneath a colorless pericarp is blue-gray. White hulls 
over a blue aleurone cause the grain to appear bluish or bluish gray. 
Black hulls over a blue aleurone give, of course, a black appearance. 
The anthocyanin is always violet in the hulls and in the pericarp, 
showing that these tissues are in an acid condition, and always blue 
in the aleurone layer, showing an alkaline condition. The occurrence 
of anthocyanin in the pericarp of hull-less barleys is more significant 
than its production in the aleurone layer. 



BIBLIOGRAPHY. 

1. Atterberg, Albert. 

1889. Die Erkennung der Haupt-Varietaten der Gerste in den Nordeuro- 
paischen Saat- und Malzgersten. In Landw. Vers. Stat., Bd. 36, p. 
23-27. 

2. 

1899. Die Varietaten und Forinen der Gerste. In Jour. Landw., Bd. 47, 
Heft 1, 1-44. 

3. Beaven, E. S. 

1902. Varieties of barley. In Jour. Fed. Inst. Brewing, v. 8, uo. 5, p. 542- 
593, 12 fig. Discussion, p. 594-600. 

4. BlFFEN, R. H. 

1905. The inheritance of sterility in the barleys. In Jour. Agr. Sci., v. 1, 
pt. 2, p. 250-257, illus. 

5. Blaringhem, Louis. 

1904. Le laboratoire d'essais de seniences de Svalof (Suede). In Bui. Mus. 
Hist. Nat. [Paris], no. 7, p. 514-519. 

6. 

1905. La notion d'espece ... In Rev. Idees, ann. 2, no. 17, p. 362-380, 8 fig. 

7. 

1908. La variation des formes vegetales. In Rev. Gen. Bot, t. 20, no. 230, 
p. 49-66, 11 fig. 



1910. Etudes sur l'Anielioration des Crus d'Orges de Brasserie. 288 p., 
17 fig., 20 pi. Paris. 

9. Brenchley, "Winifred E. 

1912. The development of the grain of barley. In Ann. Bot., v. 26, no. 103, 
p. 903-928, 22 fig. 

10. Broili, Josef. 

1906. Ueber die Unterscheidung der zweizeiligen Gerste — Hordeum dis- 
tichum — am Korne ... 60 p., 3 pi. Jena. 

11. Brown, A. J. 

1900. Note on green-skinned light barley. In Jour. Fed. Inst. Brewing, v. 6, 
p. 480-483. Discussion, p. 483-488. 

12. Derr, H. B. 

1910. A new awnless barley. In Science, n. s., v. 32, no. 823, p. 473-474, 
illus. 

13. Fruwirth, Carl, Proskowetz, Emanuel von, Tschermak, Erich, and 

Briem, Hermann. 
1910. Die Ziichtung der vier Hauptgetreidearten und der Zuckerriibe. 
460 p., illus. Berlin. See Fruwirth, Carl. Die Ziichtung der landwirt- 
schaftlichen Kulturpflanzen, Aufl. 2, Bd. 4. 

14. Johannsen, W. L. 

1884. Om Fr0hviden og dens Udvikling hos Byg. In Meddel. ( Jarlsberg Lab., 
Bd. 2, Hefte 3, p. 103-134, 3 pi. 

37 



38 BULLETIN 137, U. S. DEPARTMENT OP AGRICULTURE. 

15. KORNICKE, F. A. 

1885. Die Arten und Varietaten des Getreides. 470 p., 10 pi. Berlin. See 
his Handbuch des Getreidebaues, v. 1. 

16. Kudelka, Felix. 

1875. Ueber die Entwickelung und den Bau der Frucht- und Sanienschale 
unserer Cerealien. In Landw. Jahrb., Bd. 4, p. 461-478, pi. 5-6. Also 
reprinted. 

17. Le Clerc, J. A., and Wahl, Robert. 

1909. Chemical studies of American barleys and malts. U. S. Dept. Agr., 
Bur. Cbem. Bui. 124, 75 p., 1 pi. 

18. Mann, Albert. 

1914. Coloration of the seed coat of cowpeas. In Jour. Agr. Research, 
v. 2, no. 1, p. 33-56, 2 fig., pi. 6. 

19. Neergaard, T. B. von. 

1889. Bestanming af kornets varieteter och sorter efter pa karnorna befint- 
liga kiinnetecken. In Allm. Svenska Utsadesfor. Arsber., 1888, p. 54-61- 

20. Newman, L. H. 

1912. Plant Breeding in Scandinavia. 193 p., 63 fig. Ottawa. 

21. Regel, Robert. 

1906. Les Orges Cultivees de l'Empire Russe. 39 p. Milan. 

22. 



1908. fachmeni s glatskimi ostfami. ( Glattgrannige Gersten.) In Bui. 
Bur. Angew. Bot., Jahrg. 1, No. 1/2, p. 5-64, 84-85. (German transla- 
tion, p. 64-85.) 

23. Flaksberger, Constantin, and Malzew, A. I. 

1910. Bazhnfeish'iia formy pshenits iachmenei i sornykh rasteni'i Rossii 
(The most important forms of wheat, barley, and weed plants of 
Russia.) In Bui. Bur. Angew. Bot., Jahrg. 3, No. 6, p. 209-282. Also 
reprinted. 

24. Tedin, Hans. 

1908. Ueber die Merkmale der zweizeiligen Gerste, ihre Konstanz und ihren 
systematischen Wert. In Deut. Landw. Presse, Jahrg. 35, No. 79, 
p. 831-832 ; No. 80, p. 841-842. 

25. Voss, A. 

1885. Versuch einer neuen Systematik der Saatgerste. In Jour. Landw., 
Jahrg. 33, p. 271-282. 

26. Wheldale, M. 

1911. On the formation of anthocyanin. In Jour. Genetics, v. 1, no. 2, 
p. 133-158. 



ADDITIONAL copies 

OF THIS PUBLICATION MAY BE PROCURED FROM 

THE SUPERINTENDENT OF DOCUMENTS 

GOVERNMENT PRINTING OFFICE 

WASHINGTON, D. C. 

AT 

5 CENTS PER COPY 



V 



WASHINGTON : GOVERNMENT PRINTING OFFICE : 19U 



NUV -* '^ 



LIBRARY OF CONGRESS 



002 682 138 1 



